In a radio communication system such as LTE (long term evolution) or LTE-A (LTE-advanced) developed by the 3GPP (Third Generation Partnership Project) or wireless LAN or WiMAX (worldwide interoperability for microwave access) developed by the IEEE (Institute of Electrical and Electronics Engineers), a base station (a base station device, a downlink transmission device, an uplink reception device, or an eNodeB) and a terminal (a terminal device, a mobile station device, a downlink reception device, an uplink transmission device, or UE) each include a plurality of transmission and reception antennas, and realize high-speed data communication by spatially multiplexing data signals using a MIMO (multi-input multi-output) technology. In addition, especially in LTE and LTE-A, high spectral efficiency is realized by using an OFDM (orthogonal frequency-division multiplexing) scheme in a downlink while suppressing peak power using an SC-FDMA (single-carrier frequency-division multiple access) scheme in an uplink.
FIG. 21 is a diagram illustrating the configuration of a communication system in LTE. In FIG. 21, a base station 2101 transmits control information regarding downlink transmission data 2104 to a terminal 2102 through a physical downlink control channel (PDCCH) 2103. First, the terminal 2102 detects the control information, and when the control information has been detected, extracts the downlink transmission data 2104 using the detected control information. This downlink transmission data might be transmission data intended for the terminal 2102 or might be transmission data shared by a plurality of terminals, such as paging or system information (NPL 1 and NPL 2.)